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Physics and Chemistry of Fracture and Failure Prevention

断裂和失效预防的物理和化学

基本信息

批准号：
11CE2003
负责人：
SHOJI Tetsuo
金额：
$ 1057.79万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for COE Research
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11CE2003/
关键词：
Physics and Chemistry of Fracture Local Approach Local Information Measurement Crack Tip Solution Chemistry Grain Boundary Chemistry Small Defect Environmentally Assisted Cracking Contact Electric Resistance 微小欠陥

项目摘要

Assurance of reliability of materials and structures with synergistic effects of combined environments by mechanical, chemical, radiation and high temperature conditions is extremely important for prevention of failure and accidents. In general, failure accidents are initiated by local damage and its extension by aging. Therefore, in order to prevent these failures, detection and evaluation of the degradation at an early stage is essential. Especially, technology for 21^<st> century will go towards more precise, higher speed, higher efficiency and higher temperature and pressure and consequently, surrounding environments which materials and structures will face to can be severer than before more.The objective of this research program is to conduct a comprehensive research on mechanics and mechanisms of fracture and to construct a failure prevention system.It has been well recognized that the macroscopic approach such as Fracture Mechanics has been successfully used for structural integ … More rity and safety assessment in purely mechanical loading condition but not in environmental condition where physical and chemical reactions at crack tip plays a crucial role in fracture. Therefore, a local approach is mandatory for mechanistic understanding of this complicated fracture from a viewpoint of physics and chemistry of fracture. Measurements of local information such as local characteristics of materials, local environment such as local water chemistry at crack tip, for examples, are essential for the local approach. In the same way, local crack tip strain and tiny defects are also of importance for the local approach. These local measurements are in the order of a few nanometer to several hundreds micrometer and several tens nano-liter to a few micro-liter. Especially, an emphasis has been placed to carry out the research on crack initiation and early stage of propagation based upon local parameters obtained by a fusion of various local information, which govern the most of the life time of the components.In this program, following research areas have been covered as, (I)mechanistic understanding of physics and chemistry of fracture, (II)-1 methodology development for local measurements of materials chemistry, (II)-2 methodology development for local measurements of crack tip water chemistry, (II)-3 methodology development for local measurements of crack tip mechanics, (II)-4 methodology development for local measurements of defects (III) construction of a prediction system of failure based upon a fusion these local information.The program has been carried out by the research group shown below who have been made a significant contribution internationally on the research areas of physic and chemistry of fracture, grain boundary engineering, raser ultrasonic microscope, intelligent instrumentations, fracture in complex systems, damage evaluation and so on. After this program, this activity has been reinforced by initiating a new research institute, Fracture and Reliability Research Institute as a new extension of former Fracture Research Institute. The Institute maintains the facilities, spaces and international research network Less

在机械、化学、辐射和高温条件的综合环境的协同作用下，确保材料和结构的可靠性对于预防失效和事故极为重要。一般来说，失效事故是由局部损伤引发的，而其扩展是由老化引起的。因此，为了防止这些故障，在早期阶段检测和评估退化是必不可少的。特别是21世纪的技术将朝着更高精度、更高速度、更高效率、更高温度和压力的方向发展<st>，材料和结构所面临的环境将比以往更加复杂。本研究计划的目标是对断裂力学和机理进行综合研究，并建立一个失效预防系统。人们已经认识到，宏观方法，如断裂学，力学已成功地应用于结构的整体性， ...更多信息在纯机械载荷条件下，而不是在裂纹尖端的物理和化学反应对断裂起关键作用的环境条件下，进行可靠性和安全性评估。因此，从断裂的物理和化学观点出发，对这种复杂断裂的机理性理解必须采取局部的方法。局部信息的测量，如材料的局部特性，局部环境，如裂纹尖端的局部水化学，例如，是必不可少的局部方法。同样，局部裂纹尖端应变和微小缺陷对局部方法也很重要。这些局部测量值在几纳米到几百微米以及几十纳升到几微升的量级。特别是，重点开展了基于局部参数的裂纹萌生和早期扩展研究，这些局部参数是通过融合各种局部信息获得的，这些局部信息支配着构件的大部分寿命。（II）材料化学局部测量的方法开发，（II）裂纹尖端水化学局部测量的方法开发，（II）裂纹尖端力学局部测量的方法开发，（II）-4局部缺陷测量的方法学开发（III）在融合这些局部信息的基础上，建立了一个故障预测系统。该计划已由以下研究小组进行，他们做出了重大贡献在断裂力学和断裂化学、晶界工程、激光超声显微镜、智能仪器、复杂系统中的断裂、损伤评估等研究领域开展了一系列国际性的研究活动，在此之后，这一活动得到了加强，成立了一个新的研究所，即断裂与可靠性研究所，作为原断裂研究所的新扩展。该研究所负责维护设施、空间和国际研究网络减